A virtual 3D model (hereinafter, simply “3D model”) includes a virtual skeleton, comprised of virtual bones arranged in a hierarchical tree structure. Surrounding the bones are polygons, such as triangles, which represent the skin of the 3D model. Movement of the polygons is tied to the movement of the bones so that the 3D model approximates real-life movement when the bones are repositioned.
When a 3D model collides with another 3D model, the resulting collision may affect the position and shape of one or both models. That is, the models move and/or deform in approximately the same manner as corresponding real-life characters would in a real-life collision.
Like reference numerals in different figures indicate like elements.